Triple-negative breast cancer (TNBC) [Oestrogen receptor (ER-, ERβ+), progesterone receptor (PR-), and human epidermal growth factor receptor 2 (HER2-), marker of proliferation Kiel 67 (Ki67high)] is described as an aggressive tumour phenotype as it has an earlier onset and is associated with higher mortality rates compared to other subtypes, with high rates of metastasis and recurrence [4–10]. Here, PGR is linked to triple-negative breast carcinoma.